Is running something like Delo 400 / Delvac MX in my '88 Fairlane a good idea? I drive about 15km downhill in the morning, and 15 uphill every day in light to moderate suburban traffic. I'll need to switch the oil from Shell Heix Super City (15w40) to other oil as Shell is discontinuing this line. I like the 'idea' of an heavy duty diesel engine oil with its better additives, if courier fleets can live with them, I don't think they should perform any less compared to the Helix City but I was just worrying about incompatability for a diesel oil in the Falcon's I6. Any opinion is appreciated.

No, no problem really. Diesel Oil should be fine in the Falc. While you're at it, you may also want to add space shuttle fuel to the fuel tank to give that extra bit of power to get you up the hill at night. And don't forget to add penguins to the radiator to help keep the water cool. LOL

No, no problem really. Diesel Oil should be fine in the Falc. While you're at it, you may also want to add space shuttle fuel to the fuel tank to give that extra bit of power to get you up the hill at night. And don't forget to add penguins to the radiator to help keep the water cool. LOL

Generally diesel engine oils have better cleaning agents & anti foam properties. Think of it this way, it's like putting LSD oil in a non LSD diff it's not gonna hurt it. Being an older (high miler?) engine it probably has a bit of varnish buildup in it & the diesel oil will be better for it.

Well, someone agrees with me. If you take the time to do a used oil analysis, you will find that Delo 400 causes less engine wear than most other oils, including your high price synthetics. As SSG said, it also has a superior additive package that can really clean all the crap out of the motor.